Many industrial applications involve laying down patterns of conductive material on a substrate to produce devices and flexible electronic circuits like, for example, Radio Frequency identification (RFID) antennas for RFID labels, bus bars for displays and transparent conductive electrodes (TCEs). A transparent conductive electrode, which may include a patterned grid of conductive material, enables transmission of visible light trough the grid. The layerage light transmission ratio may vary between 0.2% and 99.9% and for most cases enables substantial visibility through the grid. A conventional method of producing, for example, antennas for RFID labels is to chemically etch copper or aluminum foils laminated to polyester (PET) films. As the thickness of a standard copper film is between 18 microns and 35 microns and the thickness required for a typical antenna or a typical electrode is 11-15 microns, the etching process becomes very expensive and slow in addition to being not environmentally safe.
Another conventional method of producing RFID antennas or TCE's involves printing the required patterns with conductive ink based on pastes containing a high concentration of electrically conductive particles (mainly silver). The printing process is expensive and not suitable for fine patterns. The low electrical conductivity of standard inks is another drawback of this process. TCE's may be also produced by lamination metallic mesh to a substrate in a rather expensive and complicated process.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.